Combustion device

Abstract

To enable positioning of a combustion plate to a combustion casing even in a combustion apparatus without a stationary plate for a heat insulator, the stationary plate being attached to a frame flange portion in conventional technologies.SOLUTION: A combustion apparatus includes a burner 1 and a combustion casing 2. A burner frame 121 in a frame shape is a component of a combustion plate that covers an opened surface 111 of a burner body 11, and includes: a side plate portion 1212 that is bent toward the burner body 11 side from an opening circumferential edge 1211; and a frame flange portion 1213 which protrudes outwardly from the side plate portion, and is held between a flange portion 112 of the burner body and a flange portion 22 of the combustion casing 2. A protruding portion 1214 which abuts or closely faces with an inner surface of the combustion casing 2 and which positions the burner frame 121 to the combustion casing 2 is provided at the side plate portion 1212 of the burner frame 121. Preferably, the protruding portion 1214 is provided at a portion apart from an end of the opening circumferential edge 1211 of the side plate portion 1212 toward the frame flange portion 1213 side.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a combustion apparatus comprising a burner consisting of a burner body into which a mixture of gases is supplied, a combustion plate covering the open surface of the burner body, and a combustion casing having a casing flange portion at one end that is fastened to a body flange portion surrounding the open surface of the burner body. [Background technology]

[0002] Conventionally, in this type of combustion device, a combustion plate is known to be used that has a frame-shaped burner frame and a mixture permeable material that covers the opening surrounded by the burner frame from the burner body side, so that the mixture that passes through the mixture permeable material and is ejected from the opening burns inside the combustion chamber (see, for example, Patent Document 1). In this device, the burner frame has an opening periphery portion around the opening, a side plate portion that bends from the opening periphery portion toward the burner body side, and a frame flange portion that protrudes outward from the burner body side end of the side plate portion and is sandwiched between the body flange portion and the chamber flange portion.

[0003] In conventional designs, the side plates of the burner frame are quite far from the inner surface of the combustion chamber. As a result, the width of the frame flange portion of the burner frame facing the inside of the combustion chamber becomes wider. Therefore, an insulating material is provided to cover the portion of the frame flange portion facing the inside of the combustion chamber, thereby suppressing overheating of the burner frame due to radiant heat input from the flame to this portion. The insulating material is held in place by a fixing plate attached to the frame flange portion. In addition, the fixing plate is provided with positioning protrusions that abut or closely face the inner surface of the combustion chamber, thereby positioning the combustion plate relative to the combustion chamber. The reason for positioning the combustion plate relative to the combustion chamber is to prevent the flame from getting too close to the inner surface of the combustion chamber, thereby preventing overheating of the combustion chamber.

[0004] Incidentally, recently, combustion plates have been developed that reduce the distance between the side plate of the burner frame and the inner surface of the combustion chamber. In combustion devices using such combustion plates, the width of the part of the frame flange of the burner frame that faces the inside of the combustion chamber is reduced, and overheating of the burner frame can be suppressed without covering this part with insulating material. In this case, it is not necessary to attach a fixing plate for insulating material to the frame flange. However, if the fixing plate is omitted, it becomes impossible to position the combustion plate relative to the combustion chamber using the positioning protrusions provided on the fixing plate, as in conventional examples. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2017-116160 [Overview of the project] [Problems that the invention aims to solve]

[0006] In view of the above, the present invention aims to enable the positioning of the combustion plate relative to the combustion chamber even in a combustion device that omits the fixing plate for the heat insulating material that was attached to the frame flange. [Means for solving the problem]

[0007] To solve the above problems, the present invention provides a combustion apparatus comprising a burner comprising a burner body into which a mixture is supplied, a combustion plate covering the open surface of the burner body, and a combustion casing having a casing flange portion at one end fastened to a body flange portion surrounding the open surface of the burner body, wherein the combustion plate comprises a frame-shaped burner frame and a mixture permeable body that covers the opening surrounded by the burner frame from the burner body side and through which the mixture is permeable, and the burner frame comprises an opening peripheral portion around the opening, a side plate portion that bends from the opening peripheral portion toward the burner body side, and a frame flange portion that protrudes outward from the burner body side end of the side plate portion and is sandwiched between the body flange portion and the casing flange portion, wherein the side plate portion of the burner frame is provided with a projection that abuts against or closely faces the inner surface of the combustion casing to position the burner frame relative to the combustion casing.

[0008] According to the present invention, the burner frame, i.e., the combustion plate, can be positioned relative to the combustion chamber by the protrusions provided on the side plates of the burner frame. Therefore, even in a combustion device in which the fixing plate for the insulating material that was attached to the frame flange is omitted, the combustion plate can be positioned relative to the combustion chamber, and overheating of the combustion chamber can be prevented.

[0009] Furthermore, in the present invention, it is desirable that the protrusion be provided in a portion away from the end of the side plate portion on the opening peripheral edge side toward the frame flange portion side. This allows the protrusion to be separated from the flame formed by the combustion of the mixture that passes through the mixture permeate and is ejected from the opening toward the burner body side, and the input of radiant heat from the flame to the protrusion is suppressed. As a result, the temperature rise of the combustion chamber due to heat transfer to the combustion chamber via the protrusion can be suppressed.

[0010] Furthermore, in the present invention, it is desirable that the protrusions be provided only on multiple portions spaced apart in the circumferential direction of the side plate. This, unlike the case in which the protrusions are provided around the entire circumference of the side plate, reduces the heat transfer area from the protrusions to the combustion chamber, thereby suppressing the temperature rise of the combustion chamber due to heat transfer to the combustion chamber via the protrusions. [Brief explanation of the drawing]

[0011] [Figure 1]A perspective view of a combustion apparatus according to an embodiment of the present invention. [Figure 2] Figure 1 is a perspective view of the combustion apparatus, seen from the opposite side. [Figure 3] Cross-sectional view taken along line III-III in Figure 1. [Figure 4] Cross-sectional view taken along line IV-IV in Figure 3. [Figure 5] A perspective view of the disassembled combustion plate of a burner, which is a component of the combustion device of the embodiment. [Figure 6] A bottom view of the combustion plate shown above in its assembled state, seen from below. [Figure 7] (a) Enlarged cross-sectional view of the main part of the combustion device assembly, cut along the line VIIa-VIIa in Figure 6; (b) Enlarged cross-sectional view of the main part of the combustion device assembly, cut along the line VIIb-VIIb in Figure 6. [Modes for carrying out the invention]

[0012] The combustion apparatus of the embodiment of the present invention shown in Figures 1 to 4 comprises a burner 1 of the all-primary combustion type, which consists of a burner body 11 into which a mixture (a mixture of fuel gas and primary air) is supplied, and a combustion plate 12 that covers the downward open surface 111 of the burner body 11, and a combustion casing 2 having an upper casing flange portion 22 fastened with screws 21 to a body flange portion 112 surrounding the open surface 111 of the burner body 11. A heat exchanger 3 for hot water supply is housed inside the combustion casing 2.

[0013] The heat exchanger 3 is a fin-tube type heat exchanger equipped with numerous fins 31 and multiple heat-absorbing tubes 32 that penetrate these fins 31. Multiple U-bent tubes 33 are provided on the outside of the side plates 23, 24 on one and the other side of the combustion chamber 2, connecting two adjacent heat-absorbing tubes 32, 32, so that all heat-absorbing tubes 32 are connected in series. In addition, a tube 34 with a water inlet 34a at its end is connected to the upstream heat-absorbing tube 32.

[0014] Also, referring to FIG. 4, inside the upper part of the heat exchanger 3 on the front side plate 25 of the combustion chamber 2, three water channels 41, 45, 49 made of pipes are arranged in order from bottom to contact the side plate 25. Inside the upper part of the heat exchanger 3 on the rear side plate 26 of the combustion chamber 2, three water channels 43, 47, 4 11 made of pipes are also arranged in order from bottom to contact the side plate 26. Also, on the outside of the side plate 23 on one lateral side of the combustion chamber 2, as shown in FIGS. 1 and 3, a connecting pipe 35 connecting the heat absorption pipe 32 at the downstream end of the heat exchanger 3 to the first water channel 41 is provided. Further, in the part of the side plate 23 above the heat exchanger 3, a fourth water channel 44 connecting the third water channel 41 and the fifth water channel 43, an eighth water channel 48 connecting the seventh water channel 47 and the ninth water channel 49, and an twelfth water channel 4 11 connected to the 12 are provided. Also, on the side plate 24 on the other lateral side of the combustion chamber 2, as shown in FIGS. 2 and 3, a second water channel 42 connecting the first water channel 41 and the third water channel 43, a sixth water channel 46 connecting the fifth water channel 45 and the seventh water channel 47, and a tenth water channel 4 11 connecting the ninth water channel 49 and the eleventh water channel 4 10 are provided above the heat exchanger 3. Each of the second, sixth, and tenth water channels 42, 46, 4 10 and each of the fourth, eighth, and twelfth water channels 44, 48, 4 12 are composed of depressions in the lateral inward direction formed in the side plates 24 and 23 and covers 41 attached to the outer surfaces of the side plates 24 and 23 to cover these depressions. The water heated by the heat exchanger 3 flows sequentially into the first water channel 41 to the twelfth water channel 4 12 and is supplied from the hot water outlet 42 provided at the end of the twelfth water channel 4 12 to a hot water pipe (not shown) connected thereto. And the water flowing through these first to twelfth water channels 41~4 12 cools each side plate 23~26 of the combustion chamber 2.

[0015] In addition, on the front side plate 25 of the combustion chamber 2, an electrode component 5 is mounted which has an ignition electrode 51, a ground electrode 52, and a pair of frame rods 53, 53 that penetrate the side plate portion between the fifth water passage 45 and the ninth water passage 49 and project into the combustion chamber 2. Note that a viewing window 54 through which the inside of the combustion chamber 2 can be viewed is attached to the electrode component 5.

[0016] Next, the burner 1 will be described in detail. An inlet 113 for connecting an external fan that supplies the air-fuel mixture is provided in the burner body 11. A check valve 13 is mounted on the inlet 113 to prevent the air-fuel mixture remaining in the burner body 11 when the fan stops from flowing back to the fan side.

[0017] Referring also to FIG. 5, the combustion plate 12 has a frame-shaped burner frame 121 and a mixture-permeable body 123 that covers the opening 122 surrounded by the burner frame 121 from the burner body 11 side (above) and through which the air-fuel mixture permeates. The mixture-permeable body 123 can be composed of a woven or non-woven fabric of heat-resistant fibers such as metal fibers, or a porous sintered body or the like. Further, a distribution plate 124 having a large number of distribution holes 124a formed on the back surface (upper surface), which is the upstream side surface of the air-fuel mixture flow direction of the mixture-permeable body 123, is overlaid. Then, the air-fuel mixture supplied into the burner body 11 is ejected from the opening 122 through the distribution holes 124a and the mixture-permeable body 123 and undergoes complete primary combustion (combustion that does not require secondary air). Note that the cross-sectional shape of the opening 122 along the front-rear direction is curved in an arc shape as shown in FIG. 4, and the mixture-permeable body 123 and the distribution plate 124 are similarly curved in an arc shape in the cross-sectional shape along the front-rear direction.

[0018] The burner frame 121 has an opening periphery portion 1211 around the opening 122, a side plate portion 1212 that bends upward from the opening periphery portion 1211 toward the burner body 11, and a frame flange portion 1213 that protrudes outward from the upper end of the side plate portion 1212. A stepped constricted portion 1211a is provided on the inner side of the opening periphery portion 1211. The combustion plate 12 is assembled by overlapping the periphery of the mixed gas permeator 123 with this constricted portion 1211a, and overlapping the distribution plate 124 on the back surface of the mixed gas permeator 123, and then spot welding the periphery of the distribution plate 124 to the outer opening periphery portion 1211 on the constricted portion 1211a at regular intervals. The frame flange portion 1213 is sandwiched between the body flange portion 112 and the casing flange portion 22. Furthermore, a packing 6 is interposed between the frame flange portion 1213 and the body flange portion 112 to ensure a seal between the burner body 11 and the combustion plate 12. As clearly shown in Figure 7, the packing 6 has a portion 61 that protrudes outward from the frame flange portion 1213, and this portion 61 is interposed between the body flange portion 112 and the housing flange portion 22 to ensure a seal between the body flange portion 112 and the housing flange portion 22.

[0019] In this embodiment, the distance between the side plate portion 1212 of the burner frame 121 and the inner surface of the combustion chamber 2, that is, the inner surfaces of each side plate 23, 24, 25, 26 of the combustion chamber 2, is short. Therefore, the width of the portion of the frame flange portion 1213 of the burner frame 121 that faces the inside of the combustion chamber 2 is narrowed, and overheating of the burner frame 121 can be suppressed even without covering this portion with insulating material. Accordingly, the fixing plate for insulating material that was conventionally attached to the frame flange portion 1213 can be omitted. However, if the fixing plate is omitted, the positioning function of the combustion plate 12 relative to the combustion chamber 2, which was provided on the fixing plate by the positioning protrusions, cannot be obtained.

[0020] Therefore, in this embodiment, a projection 1214 is provided on the side plate portion 1212 of the burner frame 121, which is positioned in close proximity to the inner surface of the combustion chamber 2 and positions the burner frame 121 relative to the combustion chamber 2. With this, the projection 1214 allows the burner frame 121, i.e., the combustion plate 12, to be positioned relative to the combustion chamber 2. Accordingly, even in a combustion device in which the fixing plate for the insulating material that was attached to the frame flange portion 1213 is omitted, the combustion plate 12 can be positioned relative to the combustion chamber 2, and overheating of the combustion chamber 2 can be prevented.

[0021] Furthermore, the protrusions 1214 are provided only on multiple portions of the side plate portion 1212 that are spaced apart in the circumferential direction. Referring specifically to Figures 6 and 7, the #1 protrusions 1214 are provided in the front-rear center of the side plate portions 1212 on both the lateral sides of the burner frame 121, and are positioned in close proximity to the inner surfaces of the side plates 23 and 24 on each side of the combustion chamber 2. Additionally, the #2 protrusions 1214 are provided at both lateral ends of the side plate portions 1212 on both the front and rear sides of the burner frame 121, and are positioned in close proximity to the inner surfaces of the side plates 25 and 26 on each side of the combustion chamber 2. This arrangement differs from providing the protrusions 1214 around the entire circumference of the side plate portion 1212, as it reduces the heat transfer area from the protrusions 1214 to the combustion chamber 2, thereby suppressing the temperature rise of the combustion chamber 2 due to heat transfer to the combustion chamber 2 via the protrusions 1214.

[0022] Furthermore, in this embodiment, each protrusion 1214 is provided in a portion of the side plate portion 1212 that is separated from the end on the opening peripheral edge portion 1211 side towards the frame flange portion 1213 side. As a result, the protrusion 1214 is separated from the flame formed by the combustion of the fuel mixture ejected from the opening 122 towards the burner body 11 side, and the input of radiant heat from the flame to the protrusion 1214 is suppressed. Therefore, the temperature rise of the combustion chamber 2 due to heat transfer to the combustion chamber 2 via the protrusion 1214 can be suppressed even more effectively.

[0023] Although embodiments of the present invention have been described above with reference to the drawings, the present invention is not limited thereto. For example, in the above embodiment, each protrusion 1212a is in close proximity to the inner surface of the combustion chamber 2, but it is also possible to provide each protrusion 1212a so as to be in contact with the inner surface of the combustion chamber 2. Furthermore, in the above embodiment, the burner 1 is arranged so that the open surface 111 of the burner body 11 faces downward, but the present invention can be similarly applied to a combustion device in which the burner body 11 is arranged so that the open surface 111 faces upward. [Explanation of symbols]

[0024] 1...burner, 11...burner body, 111...open surface, 112...body flange section, 12...combustion plate, 121...burner frame, 1211...opening periphery, 1212...side plate section, 1213...frame flange section, 1214...protrusion, 122...opening, 123...mixture permeator, 2...combustion casing, 22...casing flange section.

Claims

1. A combustion apparatus comprising a burner consisting of a burner body into which a mixture of gases is supplied, a combustion plate covering the open surface of the burner body, and a combustion casing having a casing flange portion at one end that is fastened to a body flange portion surrounding the open surface of the burner body, The combustion plate has a frame-shaped burner frame and a mixture permeable material that covers the opening surrounded by the burner frame from the burner body side, and the burner frame has an opening periphery around the opening, a side plate portion that bends from the opening periphery toward the burner body side, and a frame flange portion that protrudes outward from the burner body side end of the side plate portion and is sandwiched between the body flange portion and the casing flange portion. A combustion apparatus characterized in that the side plate portion of the burner frame itself is provided with a projection that is located on the side plate portion adjacent to the frame flange portion, away from the end on the opening peripheral edge side, and in contact with or in close proximity to the inner surface of the combustion chamber, thereby positioning the burner frame relative to the combustion chamber.

2. The combustion apparatus according to claim 1, characterized in that the protruding portion is provided only on a plurality of portions spaced apart in the circumferential direction of the side plate portion.

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